There are a handful of options here -
https://wiki.autosportlabs.com/RaceCapturePro_Lua_Scripting_Examples I have the battery-voltage version working on my Mk1 hardware. I'm having trouble combining it with reading/logging CANBus channels though. Mk1 has limited script memory available...
Code:
function onTick()
if getAnalog(7) > 13 then
startLogging()
else
stopLogging()
end
end
I don't mind having some excess non-moving data before and after each run. I prefer that to using a GPS speed trigger, so I don't miss the beginning of the run. Some of our starts have a 90-degree bend before the timing lights, to encourage less speed/burnouts at start, to reduce damage to our parking lot.